Buffer (FIFO) overflows

In some cases CPU is not able to stream the trace data quickly enough which results in overflow errors. Errors are  displayed in the Analyzer Output window and indicated in the Trace window with brown coloured lines. 

Possible solutions:

1. Limit the scope of the recorded variables.

(e.g. task/irq switches, functions, runnables). For example, configure Code Areas/Data Areas in the Analyzer Configuration dialog / Profiler.

2. Disable Program Flow tracing.

Unchecking the Analyzer Configuration dialog:

• Code in the Profiler tab.
• Coverage in the Hardware.

3. Aurora Trace Port (if used) - Use maximum number of lanes:

Increase Lane link speed in Hardware menu / CPU Options / Aurora.

4. Nexus Trace Port (if used):

• Use full trace port width available on your target and Increase MDO width in Hardware menu / CPU Options / Nexus .
• Select the highest possible trace clock  in Hardware menu / CPU Options / Nexus:
  • If supported, select double data rate.
  • Decrease the clock divider. 

5. Decrease the amount of branch/call instructions. 

An idle loop in the code constantly calls a function which returns immediately. Such programming generates excessive amounts of messages and prevents long recordings. For example, instead of:

void Idle()
{
}
…
while(true)
{
  Idle();
}

write

while(true)
{
}

Limitations inside the CPUs also exist  (e.g. on some CPU architectures only 1-bit Aurora is supported). Generated data can fill the internal buffer even before the BlueBox is able to fetch the data from the CPU. It is necessary to find a balance between the accuracy of recorded data and how much information to record.

6. Renesas RH850.

Refer to topic Trace overflows.